diff --git a/bin/rnws.js b/bin/rnws.js
index 12b1e13..e4064e4 100755
--- a/bin/rnws.js
+++ b/bin/rnws.js
@@ -7,12 +7,16 @@ const packageJson = require('../package.json');
 const createBundle = require('../lib/createBundle');
 const Server = require('../lib/Server');
 
-/**
- * Create a new array with falsey values removed
- * @param  {Array} arr An array
- * @return {Array}     The array with falsey values removed
- */
-const compact = arr => arr.filter(Boolean);
+function normalizePlatforms(options) {
+  options.platforms = [];
+  if (options.android) {
+    options.platforms.push('android');
+  }
+  if (options.ios) {
+    options.platforms.push('ios');
+  }
+  return options;
+}
 
 /**
  * Create a server instance using the provided options.
@@ -95,7 +99,7 @@ commonOptions(program.command('start'))
   .description('Start the webpack server.')
   .option('-r, --hot', 'Enable hot module replacement. [false]', false)
   .action(function(options) {
-    const opts = options.opts();
+    const opts = normalizePlatforms(options.opts());
     const server = createServer(opts);
     server.start();
   });
@@ -123,25 +127,22 @@ commonOptions(program.command('bundle'))
     false
   )
   .action(function(options) {
-    const opts = options.opts();
+    const opts = normalizePlatforms(options.opts());
     const server = createServer(opts);
+    const bundlePaths = {
+      android: opts.androidBundlePath,
+      ios: opts.iosBundlePath,
+    };
 
-    const doBundle = () => Promise.all(compact([
-      opts.android && createBundle(server, {
-        platform: 'android',
-        targetPath: opts.androidBundlePath,
-        dev: !opts.optimize,
-        minify: opts.optimize,
-        sourceMap: opts.sourceMap,
-      }),
-      opts.ios && createBundle(server, {
-        platform: 'ios',
-        targetPath: opts.iosBundlePath,
+    const doBundle = () => Promise.all(opts.platforms.map(
+      (platform) => createBundle(server, {
+        platform: platform,
+        targetPath: bundlePaths[platform],
         dev: !opts.optimize,
         minify: opts.optimize,
         sourceMap: opts.sourceMap,
-      }),
-    ]));
+      })
+    ));
 
     server.start()
       .then(doBundle)
diff --git a/lib/Server.js b/lib/Server.js
index 23abe12..5ba4fea 100644
--- a/lib/Server.js
+++ b/lib/Server.js
@@ -50,8 +50,8 @@ class Server {
    * @param {Number}  port
    * @param {Number}  packagerPort
    * @param {Number}  webpackPort
-   * @param {Boolean} enableAndroid
-   * @param {Boolean} enableIos
+   * @param {Boolean} android       Enable Android support
+   * @param {Boolean} ios           Enable iOS support
    * @param {String}  androidEntry
    * @param {String}  iosEntry
    * @param {Object}  webpackConfig The webpack config to use for webpack-dev-server
@@ -69,6 +69,7 @@ class Server {
       android: options.androidEntry,
       ios: options.iosEntry,
     };
+    this.platforms = options.platforms;
     this.resetCache = !!options.resetCache;
     this.hot = !!options.hot;
     this.webpackConfig = options.webpackConfig;
@@ -306,6 +307,7 @@ class Server {
     const hot = this.hot;
     return getReactNativeExternals({
       projectRoot: process.cwd(),
+      platforms: this.platforms,
     }).then(reactNativeExternals => {
 
       // Coerce externals into an array, without clobbering it
diff --git a/lib/getReactNativeExternals.js b/lib/getReactNativeExternals.js
index 5deb4bd..1f7b2e8 100644
--- a/lib/getReactNativeExternals.js
+++ b/lib/getReactNativeExternals.js
@@ -9,17 +9,13 @@ const Promise = require('bluebird');
  * @return {Object}         A webpack 'externals' config object
  */
 function getReactNativeExternals(options) {
-  return Promise.props({
-    androidModuleNames: getReactNativeDependencyNames({
+  return Promise.all(options.platforms.map(
+    (platform) => getReactNativeDependencyNames({
       projectRoot: options.projectRoot,
-      platform: 'android',
-    }),
-    iosModuleNames: getReactNativeDependencyNames({
-      projectRoot: options.projectRoot,
-      platform: 'ios',
-    }),
-  }).then(r => {
-    const allReactNativeModules = r.androidModuleNames.concat(r.iosModuleNames);
+      platform: platform,
+    })
+  )).then((moduleNamesGroupedByPlatform) => {
+    const allReactNativeModules = Array.prototype.concat.apply([], moduleNamesGroupedByPlatform);
     return makeWebpackExternalsConfig(allReactNativeModules);
   });
 }